One of the best nature documentaries of all time returns this weekend

“Blue Planet II” premieres in the US on Saturday, January 20 at 9 pm ET.

For the series, producers spent more than 6,000 hours underwater over four years, visiting 39 countries on 125 expeditions.

The footage they captured is breathtaking, heartbreaking, and stunning.

Earth’s oceans make life possible. They’re the reason that when the planet is viewed from space, we call it a “blue dot.”

“Blue Planet II,” a BBC Natural History Unit production that premieres in the US on Saturday, offers the most breathtaking look at the oceans yet.

The producers take viewers to the surprisingly full-of-life waters 3,280 feet deep in the Antarctic. The cameras show an octopus battling a shark in a struggle to stay alive. There’s a journey to finally discover where whale sharks give birth, and a look at how orcas use their powerful tails to kill herring with shockwaves.

At one point, the show’s production team even filmed life in the deepest parts of the ocean, seven miles down, where scientists didn’t know anything could live. Creatures there are under pressure equivalent to 50 jumbo jets stacked on top of each other.

There are at least 12 scientific papers being published based on what the teams observed.

“As filmmakers, it has been unbelievably exciting to make these films in collaboration and true unity with the scientists who can unlock the secrets to this magical world,” Orla Doherty, the producer of the new series’ second and seventh episodes, told Business Insider. “I feel like we’ve pushed the boundary of what we know about the ocean just that little bit more.”

Our blue planet

The original “Blue Planet” series came out in 2001, and was one of the first nature documentaries narrated by David Attenborough that captivated the world with the mystery and beauty of Earth’s Read More Here